Quantifying geological processes on Mars—Results of the high resolution stereo camera (HRSC) on Mars express
Résumé
This reviews ummarizes the use of High Resolution Stereo Camera( HRSC) data as an instrumental tool and itsapplication in the analysis of geological processes and landforms on Mars during the last 10 years of operation.High-resolution digital elevations models on a local to regional scale are the unique strength of the HRSCinstrument.The analysis of these data products enabled quantifying geological processes such as effusion rates oflava flows, tectonic deformation, discharge of water in channels, formation time scales of deltas, geometry ofsedimentary deposits as well as estimating the age of geological units by cratersize–frequency distributionmeasurements. Both the quantification of geological processes and the age determination allow constraining theevolution of Martian geologic activity in space and time. A second major contribution of HRSC is the discovery ofepisodicity intheintensity of geological processes on Mars.This has been revealed by comparative age dating ofvolcanic, fluvial, glacial,and lacustrine deposits.Volcanic processes on Mars have been active over more than 4Gyr, with peak phases in all three geologicepochs, generally ceasing towards the Amazonian.Fluvial and lacustrine activity phases spread a time span fromNoachian until Amazonian times, but detailed studies show that they have been interrupted by multiple and long lasting phases of quiescence. Also glacial activity shows discrete phases of enhanced intensity that may correlatewith periods o fincreased spin-axis obliquity.The episodicity of geological processes like volcanism, erosion, andglaciation on Mars reflects close correlation between surface processes and endogenic activity as well as orbitvariations and changing climate condition.